1. Field of the Invention
The present invention generally relates to a fuel injection engine, and more particularly relates to a fuel injection engine that incorporates a fuel conduit through which fuel is supplied to the engine.
2. Description of Related Art
In all fields of engine design, there is an emphasis on obtaining more effective emission control, achieving better fuel economy and increasing power output. This trend has led to the use of fuel injection systems, as opposed to carburetors, as the engine charge former.
Some fuel injection systems inject fuel into the air intake manifold. Direct fuel injection systems inject fuel directly into the combustion chamber. Direct fuel injection systems potentially have significant advantages over indirect fuel injection systems including improved emission control. Marine engines, such as outboard motors, can employ direct injection systems.
A direct injection system incorporates a high-pressure fuel pump to pressurize the fuel entering the combustion chamber. Typically, the pressure of the fuel is higher than the pressure in the combustion chamber at the compression stroke to minimize the particle size of the injected fuel and to improve the penetration of the injected fuel into the high-pressure combustion chamber.
In general, engines can employ a mechanical high-pressure pump for pressurizing the fuel. The engines can also incorporate a fuel pressure sensor to detect the fuel pressure. The detected signal may be used in an electrical control system to control the engine operation. For example, an electronic control unit (ECU) of the engine may use the fuel pressure signal for adjusting the amount of injected fuel under certain conditions. For example, the amount of injected fuel may be adjusted when the engine is in a start up operation.
Pressurized fuel can be supplied to a fuel injector through a fuel rail. The fuel rail preferably is made of a metal material and is rigidly affixed to the engine. An ECU can be disposed close to the fuel rail. The fuel pressure sensor can be mounted to the fuel rail for easy connection with the ECU.
The fuel pressure sensor can incorporate electric circuit elements in addition to a pressure sensor. Such elements may include, for example, amplifying circuit elements that amplify the detected signal and temperature compensating circuit elements that adjust the detected signal in complying with temperature changes.
Additionally, the fuel rail can be mounted to the engine at multiple bosses projecting therefrom. Typically, the engine gets very hot during operations and portions of the engine can expand.